It has been a long-standing objective of medical science to implant sensors inside the human body that continuously and accurately determine changes in metabolites;measure the concentration of biothreats or therapeutics;and provide early detection of disease prior to the onset of symptoms. That vision of implantable sensors has not yet been realized largely due to the body's immune response to implants. Diabetes mellitus is a complex, multifactorial disease affecting the length and quality of life of an affected individual. Long-lasting implantable sensors that allow continuous monitoring of glucose will be an invaluable management tool for patients afflicted by this chronic and costly disease. However, currently available sensors are inaccurate and prone to failure. The largest hurdle to developing implantable biosensors is the foreign body response (FBR). Tissue integrating biosensors may allow reliable sensor function despite the FBR. The goal of this Phase I SBIR is to assess the biocompatibility of sensor materials that encourage capillary growth in and throughout the sensor compared to sensor materials that do not permit capillary ingrowth. A bioluminescence technique developed for tumor analysis, which permits high resolution (20 um) visualization of glucose and other metabolites in tissues will be utilized. In addition to commonly used biocompatibility measures of microvasculature density, collagen content and cellular response, the bioluminescence technique will be used to determine the extent to which glucose gradients exist in and around tissue-integrating sensor scaffolds. ) PUBLIC HEALTH RELEVANCE: Diabetes is a devastating and costly chronic disease affecting nearly 25 million people in the US alone and amounting to $200B in annual healthcare expenditures. The company's goal is to develop a self- calibrating, implantable continuous glucose monitor (CGM) with a minimum operational life of 3 months and a longer-term goal of 6-12 months, starting with this SBIR Phase I project to characterize the biocompability of the novel sensor scaffold materials. Implementation of this technology will motivate and enable diabetic patients to more tightly control their glucose levels without fear of severe glucose lows, and will reduce the diabetes disease burden on the healthcare system.